let S be non empty set ; for R being total Relation of S,S
for BASSIGN being non empty Subset of (ModelSP S)
for f1, f2 being Assign of (BASSModel (R,BASSIGN)) st ( for s being Element of S st s |= f1 holds
s |= f2 ) holds
SIGMA f1 c= SIGMA f2
let R be total Relation of S,S; for BASSIGN being non empty Subset of (ModelSP S)
for f1, f2 being Assign of (BASSModel (R,BASSIGN)) st ( for s being Element of S st s |= f1 holds
s |= f2 ) holds
SIGMA f1 c= SIGMA f2
let BASSIGN be non empty Subset of (ModelSP S); for f1, f2 being Assign of (BASSModel (R,BASSIGN)) st ( for s being Element of S st s |= f1 holds
s |= f2 ) holds
SIGMA f1 c= SIGMA f2
let f1, f2 be Assign of (BASSModel (R,BASSIGN)); ( ( for s being Element of S st s |= f1 holds
s |= f2 ) implies SIGMA f1 c= SIGMA f2 )
assume A1:
for s being Element of S st s |= f1 holds
s |= f2
; SIGMA f1 c= SIGMA f2
let x be object ; TARSKI:def 3 ( not x in SIGMA f1 or x in SIGMA f2 )
assume
x in SIGMA f1
; x in SIGMA f2
then consider s being Element of S such that
A2:
x = s
and
A3:
s |= f1
;
s |= f2
by A1, A3;
hence
x in SIGMA f2
by A2; verum